Two-part piston for internal-combustion engines



July 3l, 1923. 1,463,245

J. BoLAN TWO-PART PISTON FOR INTERNAL COMBUSTION ENGINES Filed Feb. 23, 1922 mlllllfl f77/vena?" f JAMES BOLAN, 0F BOSTON, MASSACHUSETTS.

TWO-YART PISTON FOR INT'ERNAL-COMBUSTION ENGINES.

Application filed February 23, 1922. Seri-a1 No. 538,451.

7 10 all whom tmf/Ly concern i Be it known that'I, JAMES' BOLAN, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented new and useful Tmprovemcnts in Two-Part Pistons for Internal-Combustion Engines, of which the following is a specification.

This invention'relates to an improved twopartpiston for internal combustion engines.

rlhe device of this invention relates particularly to pistons for internal combustionengines with removable cylinder heads, and is adapted for use for any kind or make of internal combustion engine of the four cycle tvpe.

The object of the invention is to make a l two-part piston for internal combustion engines of light lweight as free as possible from friction, of strong and simple construction and comparatively inexpensive to manufacture. Y

Another object of the invention is to overcome piston slap or knock andl to prevent oil working up past the piston rings forming carbon -in the piston rings and in the combustion chamber. f

Another object of the invention is to provide a piston in two parts whereby the piston head, 'including the piston rings, can be easily removed from the engine without removing the connecting rod from' the crank shaft and replacing the same for the urpose of cleaning out carbon or for ad]ust ment of parts and replacing of worn parts. In internal combustion engines carbon is liable to form in the compression chamber and gather on 'the compression rings, and the underside of the `piston head and in order to secure the greatest eliciency it is very desirable that the engine should be free from carbon. Internal combustion engines having a piston in one piece connected to the connecting` rod render it necessary in order to remove the carbon that the o llvshould be drained from the oil pan, the oil pan .taken off, the connecting rod disconnected from the crank and the connectingr rod and piston pushed up through the topof the cylinder.

This is a very difficult operation, involves a large amount of labor and loss of time and all of these difficulties are overcome by the device of this invention.

In order to secure these different results, the piston of this vinvention is made of two principal parts, a head portion preferably of aluminum to'secure lightness land carrying the compression rings, and a body portion of iron, the same as the cylinder Walls, containing a wrist pin and bearings for the connecting rod. The body portion is connected to the head portion by two endless spiral springs. springs'are connected constitute a holder and forms, in effect, a portionof the piston head with which it has screw-threaded engage- Y positely disposed hubs or bearings through which the wrist. pin for the connecting rod` entends` These springshave a constant tension at 'alltimcs so that when the head is screwed on to the holder`- or spring carrier 'by rotating the saine and locked thereto by j means of :i key, the twol parts are held securely together.

An arched bridge extends over the con-` necting rod from one of said hubs to the other and between the head and the bridge which forms a part of the body .portion there is interposed a steel ball movable between two or more steeldiscsY This ball constitutes a universal pivot against which the head portion bears and through which thrust from the "explosion of the gases is transmitted directly to the body portion of thel piston. There is a space between the head portion and the body portion ot' the piston so that the head portion is free to rock in any direction, being universally pivotally mounted through said ball on the body portion. By means of this construction it isevident that the head portion Will not receive'V any side motion or thrust from the bodyv portion.

Oft/en the compression in. a cylinder becomes too weak or too strong and by my improved construction it is possible to regulate the compression by changing the dlstance of the head portion from the body portion4v and thus changing the amount of space in the compression chamber where the explosion takes place. This result is accomplished by chan ing the size of the ball or by changing the t ickness of the discs against which the ball bears, thereby reducing or increasing the compression space in the top of the cylinder.

It will be seen that the head portion being of aluminum and the body portion of iron the extra relative expansion of the aluminum part will have no effect on the body portion.

Although the oil tempered springs hereinbefore referred to are located at some distance from the heat of the piston head,

still spiral springs of various forms could be placed lower and connected to the 'spring holder or piston head and body portion without departing fromthe spirit of my invention. Inthe drawings no oiling system as used is shown, but it is understood that the usual oiling system of devices of this character will be utilized:A

'To these ends the invention consists in the improved two-part piston for internal combustion engines having, in combination, a body portion and a head portion connected together and constructed as hereinafter set forth in the specification and particularly as pointed out in the claims.

Referring to the drawings: Figure 1 is a side elevation of a two-part piston embodying my invention, a portion of a connecting rod being shown in connection therewith and brokeny away.

Fig. 2 is a sectional elevation taken on the line 2-2 of Fig. 1.

Fig. 3 is a sectional elevation taken on the line 3 3 of Fig. 2.

Fig. 4 isa sectional elevation similar to Fig. 3 but with the piston head disconnected from the body portion thereof and with the body portion shown in connection with a portion of its cylinder.

Fig. 5 is a top plan of the body portion of the piston. y

Like numerals refer to like parts throughout the several views of the-drawings.-

In the drawings, 5 is the cylinder in which is located a piston 6 consisting ofa body portion 7 and a head portion 8. The head portion is provided with annular groovesll 9 in which piston rings l0 are located. The body portion forms a loose fit in the cylinder 5 in the usual manner. while the rings 10 forma close fit therein. The 'body por# tion is provided with a pair of oppositel'y disposed inwardly extending hubs 11. 'The inner ends of the hubs 11 are connected together by `a bridge 13 which extends over the upper end of a connecting ,rod 14 which is secured by a cap 15 and screws 16 to a piston pin 17. The head portion 8 has a bushing 18 therein which is interiorly screw-threaded to receive a shank 19 formed upon a holder 20, The holder 20 has two oppositely disposed arms 21 and 22 which extend over and beyond the bridge 13 and terminate in hooks 23 and 24. `These hooks receive and positionv a pair of oppositely disposed endless springs 25 and 26. The lower part of each spring extends partly around 'a hub 1l and said springs are prevented from lateral movement toward each other by projections 27 and- 28l formed on the lower side ofthe hubs 11.

Interposed between the holder 20 and the bridge 13 which forms a part of the body portion 7 is a ball 29 which is located in a recess 30 formed in the under side of the holder 20 and bears on its upper side against a disc 31 located in the recess 30 and at its lower side said ball bears against another disc 32 located in a circular recess 33 formed in the top of the bridge 13. By this construction it will be seen that the head portion is connected to the body portion by the springs 25 and 26 and that said .head portion is universally pivotally mountlows :Assuming the parts to be in the rel ative positions illustrated in Fig. 4, the con- -nec'ting rod 14 is connected to the -pin 17 by means of the cap 15 and by the screws 16 as illustrated in Fig. 2. The piston head 8 is then lowered down toward the body portion 7 and the `shank 19 enters the bushing 18 'whereupon the piston'v head is rotated by means of a screw driver or other means inserted in a slot 36 in the top of said head until the parts assume the relative positions illustrated in Fig.. 2, whereupon the head is locked to the holder 20 by a key 35 which is driven into the slot 34 and into the slot l3.6 in the head 8. To remove the piston head portion from the cylinder and to disconnect it from the body portion 7 the reverse ofthe operation just described performed.'

It is evident that the entire piston may be removed from the cylinder if desired.

. rotated in the usual manner.

mounted thereon so as to andfthrough the ball 29 and the piston pin 17 a downward motion is imparted to the piston rod 14 whereby the crank shaftis `During the intake stroke however, the head portion 8 is drawn upwardly and carries the body portion with` `it by means of the springs 25 and 26, thus during the upward movement of the piston as a whole. the two parts thereof are held together against the suction of the intake by the springs 25 and 26.

In the operation of the piston of my in-` vention any slight variation or lateral movement'of the body portion, due to the thrust thereon of the connecting rod 14 will not be transmitted to the piston head 8 for the reason that said piston head is connected to the bodyvportion by the springs 25 andQG and through the ball 29 and therefore the piston head is pivotally mounted on the body portion 7 so that it can rock in any direction, Vthat is, it is universally pivotally mounted on the body portion.

It will be evident that from the two-part construction of the piston hereinbetorel described, and the particular manner in which the piston head is connected to the piston bodyby the springs 25` and 2G and the head being mounted on the body portion in such a manner as to be universally pivotally tip in anydirection` that any wear on the walls of the'cylinder due to lateral thrust will take place only throughout. the extent of that portion of the cylinder with which the body portion of the piston comes in contact` but that portion of the cylinder vwith which the head only comes in cont-act will notibe worn by the head as there is no llateral thrust on it, theretore the` compression will at all times be practically perfect.`

It will also be evident that it' it is desired to obtain greater compression of the gas in the compression space in the cylinder it may be accompli. hed by inserting a larger ball to take the place of the ball 29 or it it is desired to have less compression. a smaller ball may be inserted to take the place of the ball 29. The same results may be obtained by changing the discs 31 and 32 and placing thicker or thinner discs in their place to increase or diminish respectively the compression?4 in the compression space of the i cylinder.

l claim: 1. A piston for internal combustion engines having, in combination, a body portion and a head portion and pivotal means concentric and in alignment with the median head portion is universally pivotally mounted on said body portion. 2. A piston for internal combustion engines having, in combination, a body portion and a head portion and pivotal means concentric and in alignment with the median longitudinal line of said piston whereby said head portion is universally pivotally mounted on said body portion and means other than said pivotal means connecting said head portion to said body portion.` f

3.A piston for internal combustion yengines having, in combination, a body` portion and a head portion and pivotal means concentric and in alignment with the median longitudinal line ot said piston whereby said f head portion is universally pivotally mounted on said body portion and means other than said pivotal means detachably,y connecting said head portion to said body portion'.

4. A piston forinternal combustion engines having. in combination, a body portion and a head portion and pivotal means concentric and'in alignment with'the median longitudinal line of said piston whereby said head portion is universally pivotally mount-r ed on said body portion and means-other than said pivotal means yieldingly connecting said head portion to said bodyportion.

5. A pistonifor internal combustion engines having, in combination, a body portion and a head portion, a ball interposed between said body `and head portion and concentric with the median longitudinal line of said piston whereby said head portion is universally pivotally mounted upon said body portion and means connecting sai head portion to said body portion. f

6.A piston for internal combustion engines having, in combination. a body portion and a head portion. a holder detachably fastened to said head portion and constituting a portion thereof and a ball interposed between said holder and said body portion concentrically positionedv with the median longitudinal line ot said piston whereby said hea-d portion is universally pivotally mountedon said body portion.

. 7. A piston ,tor mternal combustion envlongitudinal line of said piston wherebysaid v gines having. in combination, a body portion and a head portion, pivotal means concentric and in alignment with the median longitudinal line ot said pistonwhereby said head portion is universally pivotally mounted upon said body portion and springs connecting said head portion to said body portion.,

8. A piston for internal combustion en-A gines' having, in combination, a body portion and a head portion and pivotal means concentric with the median longitudinal line of said piston whereby said head portion is universally pivotally mounted on said body portion and a pair of oppositelyjdisposed endless springs connecting said head portion to said body portion. p

y9. A piston for internal combustion engines having, in combination, a body portion and a head portion, a ball inter osed between lsaid body portion and hea portion and positioned 'concentric with the median longitudinal line of said piston whereby said head portion is universally pivotally mounted upon said body portion, a holder detachably fastened to said head portion and constituting a portion thereofand springs connecting said holder tosaid body portion. 1Q, piston forinternal combustion engines having, in combination, a body portion and a head portion, al holder detachably fastened Ito said head portion and constituting aportion thereof, and a ball interposed between said holder and said body portion andconcentric with the median longitudinal line of said piston whereby said headportion vis universally pivotally mounted on said body POI'tOnf i l1. A piston for internal combustion engines having, in combination.l a body p0rtion and a head portion, a holder detachablv fastened to said head portion` andconstituting a portion thereof, a ball interposed between said holder andy said body portion and concentric with the median longitudinal i line of said piston whereby said head portion is universally pivotally mounted on said body portion and a pair of oppositely disposed endless springs connecting said holder to said body portion.

121 A piston for internal combustionengines having, in combination, a body portion and a head portion, al holder detachably fastened to said head portion and` constituting a portion thereof, a ball interposed between said holder and said body portion and vconcentric with the median longitudinal line of said piston, a bearing Imember in said holder and a bearing member in said body portion, said bearing members being adapted to bear against diametrically opposite sides of said ball and yielding means connecting said holder to said'body portion whereby said head portionv is universally pivotally mounted von said body portion. y

13. A piston for internal'combustion engines having, in combination, a body portion and .a head portion,- hubs extending` transversely of said body portion, pivotal means concentric with the median longitudinal line of said iston whereby said head portion is universa ly pivotal-ly mounted on said body portion and a pair of oppositely disposed springs engaging 'saidl head portion and transversely extending hubs, a piston pin eX- tending through `said transversely extending hubs and across saidy body portion and a connecting rod connectedl to said piston pin.

14. A piston for internal combustion engines havin in combination, a body portion and a hea portion, a holder detachably fastened to said head ortion and constituting :a portion thereo a key locking said holder to said head portion and pivotal means concentric and aligning with the median longitudinal line of said piston, whereby said head portion is universally pivotally mounted on said body portion and detachable therefrom. i

15. A piston for internal combustion engines having, in combination, a body portion and a head portion, a ball interposed between said body port-ion and head portion and positioned concentric with the median longitudinal line of said iston whereby said head portion is luniversally pivotally mounted upon said bodyy portion and a disc interposed between said ball and one of the other of said parts and `constituting means for changing the distance of the head from the bod portion whereby the compression space in t ie cylinder may be changed.

16.'A piston forL internal combustion engines havinggin combination, a body portion and a head` portion, a ball interposed between said Ybodyportion, and head portion and"y ositioned concentrick with lthe median longitudinal line of said piston whereby said head portion is universally. pivotally mount` edupon said body portion, a disc interposed between said ball and one of the other of said parts and constituting means for changing the distance ofthe head from the body portion whereby the compression space in thc cylinder may be changed and springs connecting said head portion to said body portion.

17. A pistonfor internal combustion engines having, in combination, a body portion and a head portion and pivotal means concentric and in alignment with the median longitudinal line of said piston whereby said head portion is universally pivotally mount ed on said body portion, a piston pin extendino' across said body portion, a connecting ro eno'aging said piston pin, a cap engaging said piston pin and means to clamp said cap and connecting rod to said piston pin` said clamping means being adapted to be manipulated from the front or explosion end of the body ortion of said piston lto clamp said cap an connecting rod tosaid piston pin or to unclamp saidmcap and connecting rod from said piston pin. l.

, 18. A pistony for internal combustion engines having, in combination, a body portion and a head ortion andpivotal means con centric and 1n alignment with the median longitudinal line of said piston' whereby said head portion is universally pivotally mounted on said body portion, Va piston pin extending across said body portion, a connecting rod engaging said piston pin and means to connect said connecting rod to said piston pin, said connecting In testimony whereof I have hereunto ser means being adapted to be manlpulated my hand 1n presence of two subscribing wit from the iront or explosion end of the body nesses.

portion of said piston to connect said con- JAMES BOLAN. 5 meeting rod to said piston pin or to dscon- W'tnesses: 4

neet said connecting rod from said piston CHARLES S. GoomNG,

pin. FRANKLIN E, Low. 

